Spectral Properties And Optical Fiber Preparation Of Thulium Holmium Co-doped Tellurite Glass

At present,the mid-infrared laser has very broad application prospects in important fields such as medical treatment and environmental monitoring,therefore,the study of mid-infrared laser materials has far-reaching significance.The mid-infrared 2.0μm band lasers generally use thulium and holmium ions as the activation ions of the gain medium.There are many researched rare earth doped laser materials,mainly covering glass,crystal,ceramics and so on.The influence of rare earth ion luminescence,especially in the mid-infrared band,is mainly affected by hydroxyl group concentration,non-radiative transition,and concentration quenching.In order to obtain effective mid-infrared emission,materials with low phonon energy are often selected as the matrix material,and tellurite glass materials have the advantages of low phonon energy,wide infrared spectral range,and good chemical stability,and are expected to become excellent mid-infrared matrix material for band laser.In this paper,the optical properties of thulium holmium co-doped tellurite glass and the preparation of glass optical fiber are studied.To study the changes in the concentration and ratio of Tm³⁺ions and Ho³⁺ions and the effect of hydroxyl content in the matrix on the fluorescence emission of Ho³⁺ions in the 2.0μm band,and prepare tellurite glass materials with excellent spectral performance;Phosphate double-clad glass optical fiber matches the performance parameters between the core glass and the cladding glass,and completes the preparation of double-clad optical fiber and related performance testing.The specific work is as follows:1.The effect of doping Tm³⁺ion and Ho³⁺ion in the tellurite glass matrix on the fluorescence performance of Ho³⁺ion in the 2.0μm band was studied.First,doping a certain concentration of Tm³⁺ions into the tellurite glass matrix,and adjusting the concentration of the Ho³⁺ions to study the effect of the Ho³⁺ion concentration change on the fluorescence performance of the Ho³⁺ions in the tellurite glass matrix;doped with a certain concentration of Ho³⁺ions,the effect of changes in Tm³⁺ion concentration on the fluorescence performance of Ho³⁺ions in tellurite glass matrix was studied by changing the concentration of Tm³⁺ions.2.Studying the effect of different water removal methods on the hydroxyl groups in the glass matrix.First,the effect of pure physical water removal method on the properties of glass materials is studied.In the melting process of glass materials,vacuum drying and high temperature drying are used to study the hydroxyl content in glass materials and the spectral properties of glass materials.Second,the introduction of glass materials The effect of a certain amount of fluoride on the hydroxyl groups and optical properties of glass materials;finally,the effect of introducing O₂+CCl₄ gas during a glass melting process on the hydroxyl content and optical properties of glass materials is studied.3.Design and preparation of double-clad glass optical fiber.Using tellurite glass as the core and inner cladding material and phosphate glass as the outer cladding material,heterogeneous double-clad multimode and single-mode optical fibers were designed and prepared.Match the refractive index between the core and the cladding:on the one hand reduce the core numerical aperture（NA）;on the other hand increase the optical fiber inner cladding numerical aperture（NA）.Match the thermal properties between the core glass and the cladding glass to ensure that the drawing temperature is similar.In the experiment,the double-clad optical fiber preform was prepared by the tube rod method,and the double-clad multimode optical fiber and single-mode optical fiber were successfully prepared by using the secondary drawing technology;the optical performance of the prepared optical fiber was tested for absorption and loss,and the fiber Optical parameters.